Radiography systems and methods for the vertebral column

ABSTRACT

A radiography system for a patient comprising a generator for generating electromagnetic radiation, a detector for detecting electromagnetic radiation, a generator support, and a detector support. The generator support supports the generator for movement of the generator according to a generator sequence specific to the patient. The detector support supports the detector for movement of the detector according to a detector sequence specific to the patient.

RELATED APPLICATIONS

This application, U.S. patent application Ser. No. 14/934,005 filed Nov.5, 2015, claims priority of U.S. Provisional Application Ser. No.62/075,649, filed on Nov. 5, 2014. The contents of the '649 applicationare incorporated herein by reference and attached hereto as Exhibit A.

This application, U.S. patent application Ser. No. 14/934,005 filed Nov.5, 2015, also claims priority of U.S. Provisional Application Ser. No.62/238,200, filed on Oct. 7, 2015. The contents of the '200 applicationare incorporated herein by reference and attached hereto as Exhibit B.

TECHNICAL FIELD

The present invention relates to radiography systems and methods and, inparticular, to radiography systems and methods configured to generateimages of a patient's vertebral column.

BACKGROUND

The term “radiography” will be used herein to refer to the use ofelectromagnetic radiation to generate an image of the human body. Oneparticular class of radiography devices uses x-rays to create an imagethat may be used as a diagnostic tool by a wide variety of health careprofessionals. Radiography systems are typically sold in a variety ofconfigurations and sizes to generate an image or images of an area ofthe body of particular interest for a given medical condition.

The present invention is of particular relevance to medical conditionsrelated to the human spine, and that application of the presentinvention will be described herein in detail. However, the principles ofpresent invention may also be used with other areas of the human body aswill be generally described below.

The human vertebral or spinal column (hereinafter “spine”) is formed bya stack of individual bone structures (vertebrae) separated byintervertebral discs (discs). Ligaments extend along the length of thespine. Anomalies in the spine may have adverse health effects.Radiography images are commonly used to diagnose anomalies of the spinefor the purpose of determining appropriate medical treatment.Improvement of the radiography image can lead to improved medicaltreatment.

The need exists for radiography systems and methods for generatingimproved radiography images to facilitate the detection and treatment ofanomalies of the human spine.

SUMMARY

The present invention may be embodied as a radiography system for apatient comprising a generator, a detector, a generator support, and adetector support. The generator generates electromagnetic radiation, andthe detector detects electromagnetic radiation. The generator supportsupports the generator for movement of the generator according to agenerator sequence specific to the patient. The detector supportsupports the detector for movement of the detector according to adetector sequence specific to the patient.

The present invention may also be embodied as a method of generating aradiography image of a patient comprising the following steps. Agenerator for generating electromagnetic radiation is provided. Adetector for detecting electromagnetic radiation is provided. Agenerator sequence specific to the patient is determined. A detectorsequence specific to the patient is determined. The generator issupported for movement according to the generator sequence. The detectoris supported for movement according to the detector sequence.

The present invention may also be embodied as a system for generatingradiographic images of a spine of a patient comprising generator, adetector, a generator support, and a detector support. The generatorgenerates electromagnetic radiation along a propagation plane. Thedetector detects electromagnetic radiation. The generator supportsupports the generator for movement of the generator according to agenerator sequence specific to the spine of the patient. The detectorsupport supports the detector for movement of the detector according toa detector sequence specific to the spine of the patient. The generatorsequence determines a position in space of the propagation planerelative to the spine of the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first example x-ray scanning system ofthe present invention;

FIG. 2 is a highly schematic side elevation view representing anoptional first step in a radiography process, an exposure taken with apatient in a front to back orientation as shown in FIG. 1;

FIG. 2A is a representation of a radiography image generated by the stepdepicted in FIG. 2;

FIG. 3 a highly schematic side elevation view similar to that of FIG. 2representing an optional step in a radiography process illustrating anexposure taken with a patient in a side orientation;

FIG. 3A is a representation of a radiography image generated by the stepdepicted in FIG. 3;

FIGS. 4-8 are a highly schematic side elevation views depicting stagesof a radiography process of the present invention with a patient in afront to back orientation;

FIGS. 9 and 10 are a highly schematic side elevation views depictingstages of a radiography process of the present invention with a patientin a side orientation; and

FIG. 11 is a perspective view of a second example x-ray scanning systemof the present invention.

Reserved

DETAILED DESCRIPTION

Referring initially to FIG. 1 of the drawing, depicted therein is aradiography system 20 constructed in accordance with, and embodying, theprinciples of the present invention. The radiography system 20 comprisesa generator 22 and a detector 24. In use, a patient 26 stands betweenthe generator 22 and the detector 24. The generator 22 projectselectromagnetic radiation towards the patient 26. An absorbed portion ofthe electromagnetic radiation projected towards the patient 26 isabsorbed by the patient's body. A passed portion of the electromagneticradiation projected towards the patient 26 passes through the patient 26and is received by the detector 24. The detector 24 is eitherphotographic film or a digital detector capable of creating an imagerepresentative of the passed portion of electromagnet radiation.

The human spine typically comprises twenty-four articulating vertebraeand nine fused vertebrae. The vertebrae are arranged in regionstypically referred to as the cervical spine (cervical vertebrae C1-C7),the thoracic spine (thoracic vertebrae Th1-Th12), the lumbar spine(lumbar vertebrae L1-L5), the sacrum (S1-S5), and the coccyx (theremaining fused vertebrae).

As shown in FIGS. 2-10, the example generator 22 and the exampledetector 24 are arranged to generate images of a target region 30comprising a plurality of lumbar vertebrae 32 and a sacrum 34. Inparticular, FIGS. 2 and 4-8 depict the L1, L2, L3, L4, and L5 lumbarvertebrae 32 a, 32 b, 32 c, 32 d, and 32 e, while FIGS. 3, 9, and 10depict the L2, L3, L4, and L5 lumbar vertebrae 32 b, 32 c, 32 d, and 32e. FIGS. 2A, 3, 9, and 10 further depict a portion of the patient'ssacrum 34. FIG. 2 illustrates that discs 36 are arranged betweenadjacent vertebrae 32. For ease of reference, the disc between the L1and L2 vertebrae 32 a and 32 b will be referred to as the first disc 36a, the disc between the L2 and L3 vertebrae 32 b and 32 c will bereferred to as the second disc 36 b, the disc between the L3 and L4vertebrae 32 c and 32 d will be referred to as the third disc 36 c, andthe disc between the L4 and L5 vertebrae 32 d and 32 e will be referredto as the fourth disc 36 d.

FIG. 1 illustrates that the generator 22 is supported by a generatorsupport structure 40 and the detector 24 is supported by a detectorsupport structure 42. FIGS. 2-10 illustrate that the generator 22defines a projection region PR, and FIGS. 1-10 illustrate that thedetector 24 defines a detector surface 44 and a detector plane DP thatis moved during use. Accordingly, FIGS. 2 and 3 schematically depict aseries of projection planes at sequential points in time identified byreference characters PP1 (FIG. 2) and PP2 (FIG. 3).

Referring for a moment back to FIG. 1, that figure illustrates a machinecoordinate system MC comprising an X-axis XM, a Y-axis YM, and a Z-axisZM and a patient coordinate system PC comprising an X-axis XP, a Y-axisYP, and a Z-axis ZP. The machine coordinate system MC and patientcoordinate system PC are oriented such that the Y-axis is verticallyaligned, while the X- and Z-axes are horizontally aligned. However, themachine coordinate system MC is oriented with respect to the radiographysystem 20 such that X-axis XM always extends in a direction extendingbetween the generator 22 and the detector 24. In contrast, the X-axis XPof the patient coordinate system PC is always oriented along front toback (anterior-posterior) directions relative to the patient 26, whilethe Z-axis ZP is always oriented along side to side (lateral) directionsrelative to the patient 26. The Y-axis YP of the patient coordinatesystem PC is always oriented along top to bottom (head to toe)directions relative to the patient 26 and is thus vertical when thepatient 26 is standing upright.

The orientation of the machine coordinate axis MC and the patientcoordinate system PC is arbitrary, but, once selected, should bemaintained to ensure proper understanding of the radiography imagesgenerated by the radiography system 20. Further, it is possible for themachine to be oriented such that the machine Y- and Z-axes YM and ZM arehorizontal and the machine X-axis XM is vertical. In this case, thepatient will likely be lying on a horizontal support surface with thepatient Y- and Z-axes YP and ZP horizontal and the patient X-axis XPvertical.

In FIGS. 2 and 3, the generator support structure 40 supports thegenerator 22 such that the generator 22 is maintained in a generatorplane GP while maintaining the projection region PR in a perpendicularrelationship with the generator plane GP. The projection region PR isthe area in which the electromagnetic radiation propagates during theprocess of generating a radiography image. The projection region PR maybe roughly cubic in shape (wide projection region) or may be narroweddown by collimation or generator tube design to be a relatively thin,almost planar shape (narrow or planar projection region). The exampleprojection region PR is configured such that the projection region PR isa wide projection region that projects onto the substantially entiresurface of the detector 24 in a conventional manner. The electromagneticradiation in the projection region PR propagates in a directionperpendicular to both the generator plane GP. When a direction isassociated with the propagation region PR, that direction is thedirection in which electromagnetic radiation propagates in theprojection region.

FIGS. 2 and 3 further illustrate that the detector support structure 42supports that detector 24 such that the detector plane DP is in a fixedspatial relationship relative to the patient 26. In the example depictedin FIGS. 2 and 3, the detector surface 44 is adjacent to the targetregion 30 of the patient 26. Further, FIGS. 2 and 3 illustrate that thedetector support structure 42 supports the detector 24 such that thegenerator plane GP and the detector plane DP are parallel to each otherand the projection region PR is perpendicular to both the generatorplane GP and the detector plane DP.

And as shown in FIG. 1, the patient 26 is standing upright. In thisconfiguration, the generator plane GP and the detector plane DP are bothvertical, and the projection region PR always horizontal. It should beapparent that the patient 26 may be lying prone on the bed and theprojection region PR directed up or down through the patient 26 andtowards the detector 24 as appropriate.

FIGS. 2 and 3 further illustrate that the generator 22 is configured togenerate a wide projection region and is fixed such that the projectionregion PR is also fixed relative to the fixed detector 24 and thestationary target region 30. Alternatively, with a narrow projectionregion, the generator 22 may be displaced in the direction of arrow Aalong the generator plane GP such that the projection region PR is movedrelative to the fixed detector 24 and the stationary target region 30.The process of moving the generator 22 relative to the patient 26 whilegenerating a radiography image will be referred to herein as scanning.

In FIG. 2, the patient 26 is standing in a side orientation to obtain alateral view image (i.e., patient Z-axis ZP aligned with machine X-axisXM), and, in FIG. 3 the patient is standing in a front orientation toobtain an anterior view image (i.e., patient X-axis XP aligned withmachine X-axis XM). The resulting lateral view image and anterior viewimage will be referred to as first pilot image 50 (FIG. 2A) and thesecond pilot image 52 (FIG. 3A). The pilot images 50 and 52 illustratethe orientation of the L2-L5 vertebrae 32 b, 32 c, 32 d, and 32 e inlateral and anterior planes, respectively.

As can be seen in FIGS. 2-10, the vertebrae 32 are not perfectlyaligned. For example, with reference to FIG. 2 and the patientcoordinate system PC, an anterior surface 60 of the L2 vertebrae 32 b issubstantially parallel to the Y-axis YP and orthogonal to the X-axis XP,while an anterior surface 62 of the L4 vertebrae 32 d extends at anangle of approximately thirty degrees with respect to the vertical axisYP and at an angle of approximately sixty degrees with respect to thevertical axis YP. Similarly, with reference to FIG. 3 and the patientcoordinate system PC, a first lateral surface 70 of the L5 vertebrae 32e is substantially parallel to the Y-axis YP and orthogonal to theX-axis XP, while a first lateral surface 72 of the L3 vertebrae 32 cextends at an angle of approximately thirty degrees with respect to thevertical axis YP and at an angle of approximately sixty degrees withrespect to the vertical axis YP. The angles defined by the vertebrae 32may thus compound such that, not only are the vertebrae angled withrespect to either horizontal and vertical, the vertebrae 32 may bearranged along a curved and/or twisted path moving along the spine.

Accordingly, each particular arrangement of vertebrae 32 will thusdefine at least one curved vertebral path. A first example vertebralpath is depicted at 80 in FIG. 2 and is associated with an anterior faceof the spine within the target region 30. A second example vertebralpath is depicted at 82 in FIG. 3 and is associated with first lateralface of the spine within the target region 30. Additional vertebralpaths may be associated with posterior face and second lateral face ofthe spine within the target region 30.

However, as is apparent from the discussion above and FIGS. 2 and 3,during the process described with reference to FIGS. 2 and 3 theprojection region PR is always parallel to the X-axes XM and XP and tothe Z-axes ZM and ZP. Accordingly, with angled vertebrae, images such asthe pilot images 50 and 52 generated by the processes described withreference to FIGS. 2 and 3 may not clearly show the details of the spacebetween adjacent vertebrae 32.

For example, FIG. 2 illustrates that, because of the curvature of thespine associated with the example vertebrae 32 a-e, a projection planePP1-A along which electromagnetic radiation in the projection region PRextends through both the L4 vertebrae 32 d and the L5 vertebrae 32 e.Similarly, FIG. 3 illustrates that the curvature of the spine as definedby the example vertebrae 32 b-e requires that a projection region PP2-Aextend through both the L3 vertebrae 32 c and the L4 vertebrae 32 d. Thearrangement of the vertebrae 32 in both of these cases may obscurecertain details of the vertebrae and/or the disc 36 or vertebral spacetherebetween.

In the example radiography system 20, a unique image plan comprising agenerator sequence and/or a detector sequence is computed based on thephysical structure of a specific patient. The image plan may be embodiedas computer code that determines a generator position PG and detectorposition PD and a propagation angle α and a detector angle β at anypoint in time. In a two dimensional system, the generator position andangle may be generally represented as PG(XM,YM, α), while the detectorposition and angle may be represented as PD(XM,YM, β). Typically, α andβ are complementary. A three dimensional system would use a notationsuch as PG(XM,YM,ZM, α1, α2) and PD(XM,YM,ZM, α1, α2) to represent thegenerator position and angle and detector position and angle,respectively.

In the example depicted in the drawing, the particular angularrelationships among the vertebrae 32 in the target region 30 is shown inthe pilot images 50 and 52. In particular, at least some of the relevantangular relationships among individual vertebrae 32 in the target region30 are shown in the first and second pilot images 50 and 52, and imagesor data such as that displayed in the pilot images 50 and 52 may be usedto generate image plan.

The generator sequence and detector sequences comprising the image plandetermine a positional and directional relationship of the generator 22and detector 24, respectively, in two or three dimensions to allow thegeneration of one or more radiography images associated with the shapeof a particular spine. The shape of a particular spine may be determinedbased on, for example, data such as one or more of pilot images 50 and52. In addition, the position and angle of the upper and lower surfacesof the vertebrae 32 may be taken into account when determining one orboth of the generator sequence and the detector sequence forming theimage plan. The characteristics of a particular spine will determine theimage plan, and the image plan may be calculated or developed based onthe generator sequence and detector sequence as necessary to allow ameaningful radiographic image to be obtained from the detector 24.

In particular, assuming a known relationship of the patient coordinatesystem PC with respect to the machine coordinate system MC, thegenerator 22 and detector 24 may be arranged and oriented within themachine coordinate system MC as necessary to direct the projectionregion PR so that the projection region PR is substantially orthogonalto a vertebral path associated with the spinal face of interest. Therelationship of the patient coordinate system PC with respect to themachine coordinate system MC need not be fixed but must be known at anygiven point in time to compute the generator sequence and/or detectorsequence and to understand the resulting radiographic image.

Referring now to FIGS. 4-7, depicted therein is a relatively simpleexample of the generation of a radiography image or two or more (aplurality) radiography images using the principles of the presentinvention. For simplicity in describing the example depicted in FIGS.4-7, the generator 22 and detector 24 are moved from a home position toany one or more points along a generator plane GP (parallel to XM) andangular movement is limited to a predetermined plane (XM,YM). In a morecomplex system, the generator 22 and detector 24 may be arranged at anypoint in three-dimensional space and may be rotated or pivoted to allowangular movement in any direction from that point in three-dimensionalspace.

In the example depicted in FIGS. 4-7, a generator sequence is computedthat determines a position and angle of the generator 22 at any point intime based on characteristics of the target region 30. Thecharacteristics of the particular target region 30 may be determinedbased on at least one of the pilot images 50 and 52 described above.Similarly, a detector sequence is computed that determines a positionand angle of the detector 24 at any point in time based on at least oneof the pilot images 50 and 52 described above. In the process depictedin FIGS. 4-7, the detector 24 is formed by a planar structure 90 such asa photographic plate or array of digital sensors. Four example points intime are depicted in FIGS. 4-7, respectively. These points may be insuccession to form a single image (scanning) or may be associated withdiscrete images taken in any order. In either case, a narrow projectionregion or a wide projection region may be used.

At a first point in time depicted in FIG. 4, a first projection regionPR1 is directed between the L1 and L2 vertebrae 32 a and 32 b andthrough the first disc 36 a. In this case, a position and angle of thegenerator are represented as PG1 and α1, respectively, and a positionand angle of the detector are represented as PD1 and β1, respectively.Assuming the first point in time is represented as t1, the system may becharacterized using the following notation:Position t1=(PG1;α1;PD1;β1).

In the situation depicted in FIG. 4, the projection region PR1 issubstantially horizontal and the detector plane DP is substantiallyvertical, so α1 is zero degrees and β1 is ninety degrees. At least aportion of the image associated with the orientation of the projectionregion PR1 will thus provide a clear view of the first disc 36 a. Thedetector 24 may be also moved up as shown by arrow B to prevent repeatedexposure of the same portion of the film structure 90 during a scanningprocess.

At a second point in time depicted in FIG. 5, a second projection regionPR2 is directed through the L2 vertebrae 32 b. In this case, thegenerator 22 has been rotated as shown by arrow C such that theprojection region PR2 is angled slightly with respect to horizontal. Thedetector 24 has also been rotated as shown by arrow D such that thedetector plane DP is angled with respect to vertical to ensure that thesecond projection region PR2 is substantially orthogonal to the detectorplane DP. In this case, a position and angle of the generator arerepresented as PG2 and α2, respectively, and a position and angle of thedetector are represented as PD2 and β2, respectively. Assuming thesecond point in time is represented as t2, the system may becharacterized using the following notation:Position t2=(PG2;α2;PD2;β2).

In the situation depicted in FIG. 5, the projection region PR2 and thedetector plane DP are angled with respect to horizontal, so α2 isapproximately twenty degrees and β2 is approximately seventy degrees. Atleast a portion of the image associated with the projection region PR2will thus provide a clear view of the L2 vertebrae 32 b. Again, thedetector 24 may be moved as shown by arrow B to prevent repeatedexposure of the same portion of the film structure 90 during a scanningprocess.

At third and fourth points in time as depicted in FIGS. 6 and 7, thirdand fourth projection planes PP3 and PP4 are directed between the L3 andL4 vertebrae 32 c and 32 d and through the third disc 36 c. If theprocess involves successive exposures taken during a scanning process,the third projection region PR3 at the third point in time indicates thebeginning of the scan of the third disc, and the fourth projectionregion PR4 at the fourth point in time indicates the end of the scan ofthe third disc.

Again, the generator 22 is rotated as shown by arrow C such that theprojection planes PP3 and PP4 are angled slightly with respect tohorizontal. The detector 24 also rotates as shown by arrow D such thatthe detector planes DP and DP are angled with respect to vertical toensure that the projection planes PP3 and PP4 are substantiallyorthogonal to the detector plane DP. In this case, a position and angleof the generator are represented as PG3 and PG4 and α3 and α4,respectively, and a position and angle of the detector are representedas PD3 and PD4 and β3 and β4, respectively. Assuming the third andfourth points in time are represented as t3 and t4, the system may becharacterized using the following notation:Position t3=(PG3;α3;PD3;β3).Position t4=(PG4;α4;PD4;β4).

In the situation depicted in FIGS. 6 and 7, the projection planes PP3and PP4 and the detector plane DP are angled with respect to horizontal,so α3 is approximately thirty degrees, α4 is approximately fortydegrees, β3 is approximately sixty degrees, and β4 is approximately 50degrees. The portion of the image associated with the projection planesPP3 and PP4 will thus provide a clear view of the third vertebral disc36 c. Again, the detector 24 may be moved up as shown by arrow B toprevent repeated exposure of the same portion of the planar filmstructure 90 during a scanning process.

While four points in time are depicted and described herein, theradiography process may include only a single point in time, more orless than four points in time. Additional points in time may be outsidethe period bracketed by t1 and t4 and between any of the time points t1,t2, t3, and t4.

The resulting radiography image will be one or more two-dimensionalimages generally corresponding to the target region 30. If the image isthe composite of a plurality of discrete exposures taken as part of ascanning process, the image will correspond to a projection of the spinealong a straight line. A scan image may contain less information aboutcharacteristics of the spine such as curvature but will provide betterinformation about the individual vertebrae and the vertebral spacesbetween the vertebrae, including the vertebral discs.

Referring now to FIG. 8, depicted therein is another simple example ofthe generation of a radiography image using the principles of thepresent invention. Again, for clarity the generator 22 and detector 24are moved along generator plane GP and angular movement is limited to apredetermined plane. However, the generator 22 and detector 24 may bearranged at any point in three-dimensional space and angular movementmay be in any direction from that point in three-dimensional space.

In the example depicted in FIG. 8, a generator sequence is computed thatdetermines a position and angle of the generator 22 at any sampling timepoint within a larger sampling time period based on characteristics ofthe target region 30. The characteristics of the particular targetregion 30 may be determined based on at least one of the pilot images 50and 52 described above. Similarly, a detector sequence is computed thatdetermines a position and angle of the detector 24 at any point in timebased on at least one of the pilot images 50 and 52 described above. Inthe process depicted in FIG. 8, the detector 24 is formed by a lineardigital detector 92 connected to a computer or the like. A singlesampling period is depicted in FIG. 8, but, as in FIGS. 4-7, theradiography process implemented by the system of FIG. 8 may be performedover a plurality of points in time.

At the point in time depicted in FIG. 8, a projection region PR isdirected between the L3 and L4 vertebrae 32 c and 32 d and through thethird disc 36 c. The projection region PR in FIG. 8 indicates thebeginning of the scan of the third disc. Again, during scanning thegenerator 22 is rotated as shown by arrow C such that projection regionPR is maintained in a substantially orthogonal orientation to thedetector plane DP. In this case, a position and angle of the generatorare represented as PG and α, respectively, and a position and angle ofthe detector are represented as PD and β, respectively. Assuming thepoint in time is represented as t, the system may be characterized usingthe following notation:Position t=(PG;α;PD;β).

In the situation depicted in FIG. 8, the projection region PR and thedetector plane DP are angled with respect to horizontal, so α isapproximately thirty degrees and β is approximately sixty degrees. Theportion of the image associated with the projection region PR is at thebeginning of the process of scanning the third vertebral disc 36 c.

While only one point in time is depicted and described in FIG. 8, theradiography process will typically include additional points in timebefore and after the time point t.

With the digital detector 92, the electromagnetic energy impinging onthe detector 24 is sampled, converted into digital data, and used withdata from successive positions to generate a radiography image comprisedof one or more discrete exposures. The detector sequence controllingmovement of the digital detector 92 thus need only make sure that thedigital detector 92 is located and angled as necessary during thesampling period to obtain a clean sample of the electromagnetic energyassociated with a particular data point.

The data collected by the digital detector 92 may be assembled and usedto create a two-dimensional image generally corresponding to the targetregion 30 laid out in a straight line. This image may contain lessinformation about characteristics of spine curvature but will providebetter information about the individual vertebrae and the vertebralspaces between the vertebrae, including the vertebral discs. Inaddition, the digital data may be combined with other data associatedwith the target region 30 to allow at least a portion of athree-dimensional model of the target region 30 to be generated. Thethree-dimensional model may further be converted into a physical modelusing computer aided manufacturing.

Referring now to FIGS. 9 and 10, depicted therein is another simpleexample of the generation of a radiography image using the principles ofthe present invention. Again, for clarity the generator 22 and detector24 may be fixed at those one or more discrete locations or may be movedalong a linear path with angular movement limited to a predeterminedplane, and the generator 22 and detector 24 may be arranged at any pointin three-dimensional space and angular movement may be in any directionfrom that point in three-dimensional space.

In the example depicted in FIGS. 9 and 10, a generator sequence iscomputed that determines a position and angle of the generator 22 at anysampling period based on characteristics of the target region 30. Thecharacteristics of the particular target region 30 may be determinedbased on at least one of the pilot images 50 and 52 described above.Similarly, a detector sequence is computed that determines a positionand angle of the detector 24 at any point in time based on at least oneof the pilot images 50 and 52 described above. In the process depictedin FIGS. 9 and 10, the detector 24 is formed by the digital detector 92connected to a computer or the like. As in FIGS. 4-7, the radiographyprocess implemented by the system of FIGS. 9 and 10 would in most casesbe performed over a plurality of points in time.

In FIGS. 9 and 10, the patient 26 has been rotated relative to thesystem to obtain a lateral image. In this case, a position and angle ofthe generator are represented as PG1 and PG2 and α1 and α2,respectively, and a position and angle of the detector are representedas PD1 and PD2 and β1 and β2, respectively. Assuming the points in timeare represented as t1 and t2, the system may be characterized using thefollowing notation:Position t1=(PG1;α1;PD1;β1).Position t2=(PG2;α2;PD2;β2).

In the situation depicted in FIGS. 9 and 10, the projection region PR1and the detector plane DP2 are angled with respect to horizontal, so α1is approximately thirty degrees, α2 is approximately forty degrees, β1is approximately sixty degrees, and β2 is approximately 50 degrees. Theportion of the image associated with the projection planes PP1 and PP2will thus provide a clear view of the vertebral space and/or discbetween the L4 and L5 vertebrae 32 d and 32 e.

While only two points in time are depicted and described herein, theradiography process will typically include additional points in time,both outside the period bracketed by t1 and t2 and between the timepoints t1 and t2.

At the points in time depicted in FIGS. 9 and 10, a projection regionPR1 and PR2 are directed between the L4 and L5 vertebrae 32 d and 32 e.These two projection regions PR1 and PR2 may be associated with discreteexposures forming separate radiography images or may be associated withthe beginning and the end of a scanning process involving more than twoexposures. In the case of a scan, the projection region PR1 in FIG. 9indicates the beginning of the scan, while the projection region PR2 inFIG. 10 indicates the end of the scan. Again, the generator 22 isrotated as shown by arrow C such that projection region PR is maintainedin a substantially orthogonal orientation to the detector plane DPduring scanning.

With the digital detector 92, the electromagnetic energy impinging onthe detector 24 is sampled, converted into digital data, and stored forfuture processing. The detector sequence controlling movement of thedigital detector 92 ensures that the detector 92 is located and angledas necessary during the sampling period to obtain a clean sample of theelectromagnetic energy associated with a particular data point.

The data collected by the digital detector 92 may be assembled and usedto create one or more two-dimensional images. With an image created by ascanning process involving a succession of exposures, the image willgenerally correspond to the target region 30 laid out in a straightline. This image will contain less information about certain spinalcharacteristics such as spinal curvature but will provide betterinformation about the individual vertebrae and the vertebral spacesbetween the vertebrae, including the vertebral discs. In addition, thedigital data may be combined with other data associated with the targetregion 30 to allow at least a portion of a three-dimensional model ofthe target region 30 to be generated. The three-dimensional model mayfurther be converted into a physical model using computer aidedmanufacturing.

A number of robotic systems may be used as or as part of the generatorsupport structure 40 and detector support structure 42 to position andangle the generator 22 and the detector 24. As one example, thegenerator 22 and detector 24 may be supported for linear movement androtation in a single plane as shown in FIGS. 4-10. Alternatively, amultiple axis robotic arm may be used to move the generator 22 and/ordetector 24 in three-dimensional space and also to rotate through theXM-YM plane and the XM-ZM plane.

The generator and detector sequences forming the image plan will directa sequence of movements required to displace the generator 22 anddetector 24 from a home position to a position at which a desiredprojection region may be obtained, at which point an exposure is taken.And if multiple images are desired or a scanning process employingmultiple exposures is performed to obtain a single image, the generatorand detector sequences will include the machine control commands and/orfeedback necessary to move the generator 22 and detector 24 to aplurality of positions. In this case, one or more exposures will betaken at each of the plurality of positions.

Turning now to FIG. 11, depicted therein is a second example radiographysystem 120 of the present invention. The radiography system 120comprises a generator 122, a detector 124, and a platform 126. In use, apatient 128 stands on the platform 126 between the generator 122 and thedetector 124. The generator 122 projects electromagnetic radiationtowards the patient 26. When a platform 126 is provided, the image planwill further comprise a platform sequence for controlling movement ofthe platform 126. The platform sequence may also be calculated based ondata such as the pilot images 50 and 52 described above. The platform126 defines an axis of rotation parallel to the machine y-axis YM and iscontrollable to move the patient such that the patient 26 rotates aboutthe patient y-axis YP.

As the generator 122 and detector 124 move according to generator anddetector sequences as generally described above, the platform 126rotates according to a platform sequence. As the absorbed portion of theelectromagnetic radiation projected towards the patient 128 and isabsorbed by the patient's body, the patient's body is rotated such thattwist or other curvature of the spine is taken into account as the scanis performed. The passed portion of the electromagnetic radiation thatis passed through the patient 128 and is received by the detector 124will thus contain information that is not obscured by asymmetricaltwists or other curvature aside from front to back or side to side.

In the second example radiography system 120, the use of the platformsequence to control rotation of the platform 126 in the XM-ZM planeallows the use of generator and detector support systems that allowlinear movement and rotation in a single plane as shown in FIGS. 4-10yet obtain data/images similar to that obtained by a three-dimensional,multiple plane system.

What is claimed is:
 1. A radiography system for a patient comprising: agenerator for generating electromagnetic radiation, where theelectromagnetic radiation is transmitted along a substantially planarprojection region; a detector for detecting electromagnetic radiation,where the detector defines a detector plane; a generator support forsupporting the generator for continuous movement of the generatoraccording to a generator sequence specific to the patient; and adetector support for supporting the detector for continuous movement ofthe detector according to a detector sequence specific to the patient;whereby as the generator support continuously moves the generatoraccording to the generator sequence, the generator continuouslygenerates electromagnetic radiation along the projection region; and thedetector support further continuously moves the detector in accordancewith the detector sequence such that the detector is displaced relativeto the generator and the detector plane is continuously supported in adesired angular relationship relative to the projection region such thatthe electromagnetic radiation generated by the generator is continuouslyreceived by the detector, and a radiographic image is formed from thedetector.
 2. A radiography system as recited in claim 1, in which thegenerator sequence determines a position in space of the projectionregion relative to the patient.
 3. A radiography system as recited inclaim 1, in which the generator sequence determines a spatial positionof and propagation angle associated with the generator.
 4. A radiographysystem as recited in claim 1, in which: the generator support supportsthe generator for linear movement and rotation within a predeterminedplane; and the detector support supports the detector for linearmovement and rotation within the predetermined plane.
 5. A radiographysystem as recited in claim 4, further comprising a platform forsupporting the patient for rotation relative to at least one of thegenerator and the detector.
 6. A radiography system as recited in claim1, in which: the generator support supports the generator for movementwithin three-dimensional space and rotation within first and secondpredetermined planes; and the detector support supports the detector formovement within three-dimensional space and rotation within first andsecond predetermined planes.
 7. A radiography system as recited in claim1, in which the generator sequence and the detector sequence aredetermined based on characteristics of a spine of the patient.
 8. Aradiography system as recited in claim 1, in which the generatorsequence and the detector sequence are determined based on at least onepilot image of a spine of the patient.
 9. A method of generating aradiography image of a patient comprising the steps of: providing agenerator for generating electromagnetic radiation, where theelectromagnetic radiation is transmitted along a substantially planarprojection region; providing a detector for detecting electromagneticradiation, where the detector defines a detector plane; determining agenerator sequence specific to the patient; determining a detectorsequence specific to the patient; supporting the generator forcontinuous movement according to the generator sequence; and supportingthe detector for continuous movement according to the detector sequence;and as the generator is continuously moved according to the generatorsequence, operating the generator to continuously generateelectromagnetic radiation along the projection region, and continuouslydisplacing the detector in accordance with the detector sequence suchthat the detector is displaced relative to the generator and thedetector plane is continuously supported in a desired angularrelationship relative to the projection region such that theelectromagnetic radiation generated by the generator is continuouslyreceived by the detector, and a radiographic image is formed from thedetector.
 10. A method as recited in claim 9, in which the step ofdetermining the generator sequence comprises the step of determining aposition in space of the projection region relative to the patient. 11.A method as recited in claim 9, in which the step of determining thegenerator sequence comprises the step of determining a spatial positionof and propagation angle associated with the generator.
 12. A method asrecited in claim 9, in which: the generator is supported for linearmovement and rotation within a predetermined plane; and the detector issupported for linear movement and rotation within the predeterminedplane.
 13. A method as recited in claim 12, further comprising the stepof rotating the patient relative to at least one of the generator andthe detector.
 14. A method as recited in claim 9, in which: thegenerator is supported for movement within three-dimensional space androtation within first and second predetermined planes; and the detectoris supported for movement within three-dimensional space and rotationwithin first and second predetermined planes.
 15. A method as recited inclaim 9, in which the generator sequence and the detector sequence aredetermined based on characteristics of a spine of the patient.
 16. Amethod as recited in claim 9, further comprising the step of generatingat least one pilot image of a spine of the patient, where the generatorsequence and the detector sequence are determined based on the at leastone pilot image.
 17. A system for generating a radiographic image of aspine of a patient comprising: a generator for generatingelectromagnetic radiation, where the electromagnetic radiation istransmitted along a substantially planar projection region; a detectorfor detecting electromagnetic radiation, where the detector defines adetector plane; a generator support for supporting the generator forcontinuous movement of the generator according to a generator sequencespecific to the spine of the patient; and a detector support forsupporting the detector for continuous movement of the detectoraccording to a detector sequence specific to the spine of the patient;wherein the generator sequence determines a position in space of theprojection region relative to the spine of the patient; and as thegenerator support continuously moves the generator according to thegenerator sequence, the generator continuously generates electromagneticradiation along the projection region; and the detector support furthercontinuously moves the detector in accordance with the detector sequencesuch that the detector is displaced relative to the generator and thedetector plane is continuously supported in a desired angularrelationship relative to the projection region such that theelectromagnetic radiation generated by the generator is continuouslyreceived by the detector, and a radiographic image is formed from thedetector.
 18. A system for generating a radiographic image as recited inclaim 17, in which: the generator support supports the generator forlinear movement and rotation within a predetermined plane; and thedetector support supports the detector for linear movement and rotationwithin the predetermined plane.
 19. A system for generating aradiographic image as recited in claim 18, further comprising a platformfor supporting the patient for rotation relative to at least one of thegenerator and the detector.
 20. A system for generating a radiographicimage as recited in claim 17, in which: the generator support supportsthe generator for movement within three-dimensional space and rotationwithin first and second predetermined planes; and the detector supportsupports the detector for movement within three-dimensional space androtation within first and second predetermined planes.